How we cite our quotes:
[…] The spirit that I have seen
May be the devil: and the devil hath power
To assume a pleasing shape; yea, and perhaps
Out of my weakness and my melancholy,
As he is very potent with such spirits,
Abuses me to damn me:
The Ghost always seems to be associated with Hamlet's is-he-or-isn't-he insanity. Here, Hamlet is concerned that the Ghost may be "the devil" and is trying to tempt him to murder Claudius without just cause. What's interesting to us about this passage is the way Hamlet (who is alone on stage at this point) wonders if being depressed has left him vulnerable to evil—which is maybe one more reason to drag his feet before committing murder.
He knew me not at first; he said I
was a fishmonger: he is far gone, far gone: and
truly in my youth I suffered much extremity for
love; very near this.
Polonius is convinced that Hamlet is "far gone, far gone" in his love for Ophelia. But—sorry, Polonius—we think it's more likely that Hamlet is likely making a naughty joke at Polonius's expense: a "fishmonger" is slang for "pimp." I.e., Hamlet knows that Polonius is basically pimping out his daughter to get at Hamlet.
HAMLET I am but mad north-north-west: when the wind is
southerly I know a hawk from a handsaw.
First, this seems to be Hamlet telling Rosencrantz and Guildenstern that he knows exactly what they're up to: spying on him. But we also included this as a little lesson in how things get lost in translation. "Handsaw" is almost certainly a corruption of "heronshaw," i.e. a heron—which sounds a lot less crazy than comparing a bird to a carpentry tool.